Method and arrangement for measuring a force or a moment, using multiple magnetic sensors

ABSTRACT

The present invention relates to a method and an arrangement for measuring a force and/or moment on a machine element extending along an axis, using the inverse magnetostrictive effect. The machine element has a magnetization region for magnetization, this region fully encompassing the axis. The arrangement includes at least one first magnetic sensor and one second magnetic sensor, each being designed to measure individually a first and a second direction component of a magnetic field that is caused by the magnetization and by the force and/or the moment. The direction components that can be measured using the first magnetic sensor have differing orientations. Likewise, the direction components that can be measured using the second magnetic sensor have differing orientations. The first magnetic sensor and the second magnetic sensor are arranged around the axis at different peripheral positions.

BACKGROUND

The present invention relates first to an arrangement for measuring aforce and/or a moment on a machine element extending along an axis withat least two magnetic field sensors using the inverse magnetostrictiveeffect. The invention also relates to a method for measuring a forceand/or a moment, wherein the force or the moment acts on a machineelement extending along an axis.

U.S. Pat. No. 8,087,304 B2 discloses a magnetoelastic torque sensor formeasuring a torque acting on a shaft. The shaft has circumferentialmagnetization areas.

From U.S. Pat. No. 2012/0296577 A1, a magnetoelastic force sensor isknown that is formed for measuring forces on an element that ismagnetized circumferentially.

U.S. Pat. No. 5,321,985 teaches a magnetostrictive torque sensor inwhich a magnetostrictive layer is deposited on the outer surface of ashaft and is positioned opposite excitation and detection coils. Atorque acting on the shaft causes material tension in themagnetostrictive layer, wherein its relative magnetic permeabilitychanges as a function of direction. The magnetic field coming from themagnetostrictive layer is measurable with the detection coils.

DE 699 36 138 T2 discloses a magnetic force sensor in which a magnetizedmaterial is exposed to a bending moment, wherein the outer magneticfield of the magnetized material can be determined with the help of asensor arrangement.

DE 600 07 641 T2 discloses a transducer element that is provided for atorque or a force sensor transducer. In this transducer element,magnetization areas are formed in a radially inner region and in aradially outer region.

From DE 603 09 678 T2, a method is known for detecting a torque in ashaft in which magnetic fields with alternating polarity are generatedthat are measured with a sensor arrangement.

U.S. 2007/0022809 A1 discloses a device for measuring torque in which alayer is formed from a magnetostrictive material in a shaft.

DE 39 40 220 A1 teaches a load sensor for measuring loads due to atorque acting on a shaft. Magnetostrictive elements in two groups aremounted on the shaft in a zig-zag pattern.

From U.S. Pat. No. 5,052,232, a magnetoelastic torque sensor is known inwhich a machine element is provided with two circumferentialmagnetostrictive coatings.

From DE 698 38 904 T2, a torque sensor with circular magnetization isknown. The magnetization is formed in a ferromagnetic, magnetostrictivematerial of a shaft and extends in a circular shape about the shaft.

U.S. Pat. No. 7,752,923 B2 discloses a magnetostrictive torque sensor inwhich a magnetically insulating layer is deposited on a shaft and amagnetostrictive layer is deposited on this insulating layer.

DE 601 05 794 T2 discloses a force-sensitive transducer element with abody made from magnetic material, wherein at least two magnetized areasthat extend at an angle to the force transmission direction and thathave opposite magnetization polarities are formed in the body.

DE 691 32 101 T2 discloses a magnetic image sensor with a wire that hasmagnetization in the circumferential direction.

From DE 692 22 588 T2, a ring-shaped magnetized torque sensor is known.

WO 2007/048143 A2 teaches a sensor with a magnetized shaft.

WO 01/27638 A1 discloses an acceleration sensor with a shaft that ismagnetized in the circumferential or longitudinal direction.

From WO 2006/053244 A2, a torque sensor is known that comprises amagnetization on a rotating shaft. The magnetization has acircumferential construction.

U.S. Pat. No. 8,191,431 B2 discloses a sensor arrangement with amagnetized shaft.

SUMMARY

The objective of the present invention lies in that, starting from theprior art, the possibilities for measuring forces and/or moments usingthe inverse magnetostrictive effect are to be expanded.

The specified objective is attained by a machine element according tothe invention and by a method according to the invention.

The arrangement according to the invention is used for measuring a forceand/or a moment on a machine element extending along an axis. The forceor the moment acts on the machine element, wherein this causesmechanical stresses and the machine element is usually slightlydeformed. The axis preferably forms a rotational axis of the machineelement.

The machine element has a magnetization area extending circumferentiallyabout the axis for a magnetization formed in the machine element. Thisarea is a magnetization area surrounding the axis, wherein the axisitself preferably does not form a part of the magnetization area. Themagnetization area has a tangential orientation with respect to asurface of the machine element extending about the axis. Themagnetization area preferably has only a tangential orientation withrespect to a surface of the machine element extending about the axis.The magnetization area preferably extends along a closed path about theaxis, wherein the magnetization area may have short gaps. Themagnetization area forms a primary sensor for determining the force orthe moment.

The arrangement further comprises at least one first magnetic fieldsensor and one second magnetic field sensor each of which form asecondary sensor for determining the force or the moment. The primarysensor, i.e., the magnetization area, is used for converting the forceto be measured or the moment to be measured into a correspondingmagnetic field, while the secondary sensors enable the conversion ofthis magnetic field into electrical signals. The first magnetic fieldsensor and the second magnetic field sensor are each formed forindividually measuring at least one first directional component and asecond directional component of a magnetic field caused by themagnetization and by the force and/or by the moment. The suitability ofthe at least two magnetic field sensors for individually measuring theat least two directional components of the magnetic field can be formeddirectly or indirectly. The at least two directional components are eachmeasurable independently from each other. The specified magnetic fieldoccurs due to the inverse magnetostrictive effect. Thus, the measurementpossible with the arrangement according to the invention uses theinverse magnetostrictive effect. The first directional componentmeasurable with the first magnetic field sensor and the seconddirectional component measurable with the first magnetic field sensorhave different orientations with respect to the axis. Likewise, thefirst directional component measurable with the second magnetic fieldsensor and the second directional component measurable with the secondmagnetic field sensor have different orientations with respect to theaxis. Thus, with each of the magnetic field sensors, different vectorcomponents of the magnetic field caused by the magnetization and by theforce and/or by the moment can be measured individually. The firstmagnetic field sensor and the second magnetic field sensor are arrangedat different circumferential positions about the axis. Thus, the firstmagnetic field sensor and the second magnetic field sensor havedifferent angles of rotation relative to the axis.

One special advantage of the arrangement according to the invention isprovided in that it enables the measurement of different vectorcomponents of the force acting on the machine element or the momentacting on the machine element. The arrangement thus enables amultifunctional measurement.

The magnetization area can be permanently or temporarily magnetized. Forpreferred embodiments of the arrangement according to the invention, themagnetization area is permanently magnetized so that the magnetizationis formed by a permanent magnetization. For alternative preferredembodiments of the arrangement according to the invention, this furtherhas a magnet for magnetizing the magnetization area, so that themagnetization of the magnetization area is basically temporary. Themagnet can be formed by a permanent magnet or preferably by anelectromagnet.

The permanently or temporarily magnetized magnetization area ispreferably magnetically neutral outside of the magnetization area in astate of the machine element unloaded by a force or by a moment, so thatno technically relevant magnetic field is measurable outside of themagnetization area.

The magnetization area is a part of the volume of the machine element.The magnetization area preferably has a ring-shaped construction,wherein the axis of the machine element also forms a middle axis of thering shape. In an especially preferred way, the magnetization area hasthe shape of a hollow cylinder that is coaxial to the axis of themachine element.

The suitability of the magnetic field sensors for measuring differentdirectional components of the magnetic field can be produced in that themagnetic field sensors each comprise two or three magnetic field sensorelements that are each formed for measuring one of the directionalcomponents of the magnetic field caused by the magnetization and by theforce and/or by the moment. The magnetic field sensor elements do nothave to be arranged in a common housing. The magnetic field sensorelements preferably have identical constructions but differentorientations.

The at least two directional components measurable with the magneticfield sensors are preferably selected from the following group ofdirections: a direction parallel to the axis, i.e., an axial direction;a direction radial to the axis, i.e., a radial direction, and adirection tangential to the axis, i.e., a tangential direction.

In one specific embodiment of the arrangement according to theinvention, at least one of the magnetic field sensors is formed for theindirect measurement of one of the directional components of themagnetic field. For example, in one ring-shaped magnetization area, theaxial directional component of the magnetic field can be measuredindirectly such that a radial directional component of the magneticfield is measured directly with an axial distance to the ring-shapedmagnetization area.

The first directional component measurable with the first magnetic fieldsensor and the second directional component measurable with the firstmagnetic field sensor are arranged preferably perpendicular to eachother with respect to the axis, e.g., tangential and radial. The axialdirection, the radial direction, and the tangential direction areperpendicular to each other.

The first directional component measurable with the second magneticfield sensor and the second directional component measurable with thesecond magnetic field sensor are arranged preferably perpendicular toeach other. The axial direction, the radial direction, and thetangential direction are perpendicular to each other.

In preferred embodiments of the arrangement according to the invention,the first directional component measurable with the first magnetic fieldsensor and the first directional component measurable with the secondmagnetic field sensor have identical orientations. Accordingly, thesecond directional component measurable with the first magnetic fieldsensor and the second directional component measurable with the secondmagnetic field sensor have identical orientations. For example, thefirst directional component of both magnetic field sensors can be theaxial direction, while the second directional component of both magneticfield sensors can be the tangential direction.

In preferred embodiments of the arrangement according to the invention,the at least two magnetic field sensors are each further formed formeasuring a third directional component of the magnetic field caused bythe magnetization and by the force and/or by the moment. The thirddirectional component measurable with the first magnetic field sensorand the third directional component measurable with the second magneticfield sensor preferably have identical orientations. The threedirectional components are preferably formed by the axial direction, theradial direction, and the tangential direction with respect to the axisof the machine element. Consequently, the first directional componentmeasurable with the first magnetic field sensor, the second directionalcomponent measurable with the first magnetic field sensor, and the thirddirectional component measurable with the first magnetic field sensorare arranged perpendicular to each other. Accordingly, the firstdirectional component measurable with the second magnetic field sensor,the second directional component measurable with the second magneticfield sensor, and the third directional component measurable with thesecond magnetic field sensor are arranged perpendicular to each other.

In preferred embodiments of the arrangement according to the invention,this further comprises a third magnetic field sensor for the separatemeasurement of at least a first and a second directional component ofthe magnetic field caused by the magnetization and by the force and/orby the moment. The preferred constructions described above for thedirectional components measurable with the first magnetic field sensorand with the second magnetic field sensor apply equally for the thirdmagnetic field sensor. For example, the third magnetic field sensor ispreferably also formed for measuring a third directional component ofthe magnetic field caused by the magnetization and by the force and/orby the moment. The three directional components are preferably likewiseformed by the axial direction, the radial direction, and the tangentialdirection with respect to the axis of the machine element.

In preferred embodiments of the arrangement according to the invention,this further comprises a fourth magnetic field sensor for individuallymeasuring at least a first and a second directional component of themagnetic field caused by the magnetization and by the force and/or bythe moment. The preferred constructions described above for thedirectional components measurable with the first magnetic field sensor,with the second magnetic field sensor, and with the third magnetic fieldsensor apply in the same way to the fourth magnetic field sensor. Forexample, the fourth magnetic field sensor is preferably also formed formeasuring a third directional component of the magnetic field caused bythe magnetization and by the force and/or by the moment. The threedirectional components are preferably likewise formed by the axialdirection, the radial direction, and the tangential direction withrespect to the axis of the machine element.

In principle, the arrangement according to the invention can alsocomprise more than four of the magnetic field sensors.

The first directional component measurable with the magnetic fieldsensors is preferably formed by the direction parallel to the axis ofthe machine element, i.e., by the axial direction.

The second directional component measurable with the magnetic fieldsensors is preferably formed by the direction radial to the axis of themachine element, i.e., by the radial direction.

The third directional component measurable with the magnetic fieldsensors is preferably formed by the direction tangential to the axis ofthe machine element, i.e., by the tangential direction.

The at least two magnetic field sensors preferably have an identicaldistance to the axis of the machine element. In principle, the at leasttwo magnetic field sensors can be arranged outside of the machineelement or also inside a hollow space of the machine element, forexample, if the machine element is formed by a hollow shaft.

The at least two magnetic field sensors are preferably arranged at thesame axial position as the magnetization area distributed about theaxis. Thus, the magnetic field sensors have the same axial position asthe magnetization area. Here, the at least two magnetic field sensorsare preferably arranged distributed about a single point of the axis.

The at least two magnetic field sensors are preferably arrangeddistributed equally about the axis. If the arrangement according to theinvention comprises exactly two of the magnetic field sensors.Consequently, these have an angle of 180° to each other with respect tothe axis. If the arrangement according to the invention comprisesexactly three of the magnetic field sensors. Consequently, two adjacentsensors of these magnetic field sensors have an angle of 120° to eachother with respect to the axis. If the arrangement according to theinvention comprises exactly four of the magnetic field sensors, twoadjacent sensors of the magnetic field sensors have an angle of 90° toeach other with respect to the axis.

In a first especially preferred embodiment of the arrangement accordingto the invention, this comprises four of the magnetic field sensors,wherein the three directional components measurable with the fourmagnetic field sensors are formed by the direction parallel to the axis,by the direction radial to the axis, and by the direction tangential tothe axis. The adjacent sensors of the four magnetic field sensors eachhave an angle of 90° to each other with respect to the axis.

In a second especially preferred embodiment of the arrangement accordingto the invention, this comprises four of the magnetic field sensors,wherein the two directional components measurable with the four magneticfield sensors are formed by the direction parallel to the axis and bythe direction tangential to the axis. The adjacent sensors of the fourmagnetic field sensors each have an angle of 90° to each other withrespect to the axis.

In a third especially preferred embodiment of the arrangement accordingto the invention, this comprises four of the magnetic field sensors,wherein the two directional components measurable with the four magneticfield sensors are formed by the direction parallel to the axis and bythe direction radial to the axis. The adjacent sensors of the fourmagnetic field sensors each have an angle of 90° to each other withrespect to the axis.

In a fourth especially preferred embodiment of the arrangement accordingto the invention, this comprises three of the magnetic field sensors,wherein the three directional components measurable with the threemagnetic field sensors are formed by the direction parallel to the axis,by the direction tangential to the axis, and by the direction radial tothe axis. The adjacent sensors of the three magnetic field sensors eachhave an angle of 120° to each other with respect to the axis.

In a fifth especially preferred embodiment of the arrangement accordingto the invention, this comprises three of the magnetic field sensors,wherein the two directional components measurable with the threemagnetic field sensors are formed by the direction parallel to the axisand by the direction tangential to the axis. The adjacent sensors of thethree magnetic field sensors each have an angle of 120° to each otherwith respect to the axis.

In a sixth especially preferred embodiment of the arrangement accordingto the invention, this comprises three of the magnetic field sensors,wherein the two directional components measurable with the threemagnetic field sensors are formed by the direction parallel to the axisand by the direction radial to the axis. The adjacent sensors of thethree magnetic field sensors each have an angle of 120° to each otherwith respect to the axis.

In a seventh especially preferred embodiment of the arrangementaccording to the invention, this comprises two of the magnetic fieldsensors, wherein the three directional components measurable with thetwo magnetic field sensors are formed by the direction parallel to theaxis, by the direction tangential to the axis, and by the directionradial to the axis. The two magnetic field sensors have an angle of 180°to each other with respect to the axis.

In one specific embodiment of the arrangement according to theinvention, the machine element extends in a first section along theaxis, so that the axis is to be viewed as a first axis. In the firstsection, the machine element has the magnetization area, so that this isto be viewed as a first magnetization area. The machine element also hasa second section in which it extends along a second axis arrangedperpendicular to the first axis. Consequently, the machine elementextends at a right angle. The arrangement according to the invention isformed both in the first section and also in the second section. Here,in the second section, the machine element has a second magnetizationarea extending circumferentially about the axis for a secondmagnetization and at least one first magnetic field sensor allocated tothe second section and a second magnetic field sensor allocated to thesecond section. The constructions of the magnetization area describedabove apply in the same way also to the second magnetization area. Theconstructions of the magnetic field sensors described above apply in thesame way also to the magnetic field sensors allocated to the secondmagnetization area. In particular, the magnetic field sensors allocatedto the second section are each formed for measuring at least a first anda second directional component of a second magnetic field caused by thesecond magnetization and by the force and/or by the moment. The firstdirectional component measurable with the first magnetic field sensorallocated to the second section and the second directional componentmeasurable with the first magnetic field sensor allocated to the secondsection have different orientations. Likewise, the first directionalcomponent measurable with the second magnetic field sensor allocated tothe second section and the second directional component measurable withthe second magnetic field sensor allocated to the second section havedifferent orientations. The first magnetic field sensor allocated to thesecond section and the second magnetic field sensor allocated to thesecond section are arranged at different circumferential positions aboutthe second axis. This special embodiment enables the measurement offorces and moments in all three spatial directions already with exactlytwo magnetic field sensors allocated to the first section and exactlytwo magnetic field sensors allocated to the second section.

The magnetization area preferably exhibits a high magnetostrictiveeffect.

The magnetization area can also be formed multiple times, so that themachine element of the arrangement according to the invention preferablyhas multiple magnetization areas. In this way, for example, theinterfering influence of external magnetic fields can be compensated.Preferably, the surrounding magnetization areas are arranged one next tothe other with axial spacing and differ only in their polarity, i.e., intheir rotational sense. Preferably, adjacent magnetization areas eachhave opposite polarities.

The machine element preferably has the shape of a prism or of acylinder, wherein the prism or the cylinder is arranged coaxial to theaxis. The prism or the cylinder is preferably straight. In an especiallypreferred way, the machine element has the shape of a straight circularcylinder, wherein the circular cylinder is arranged coaxial to the axis.For special embodiments, the prism or the cylinder has a conicalconstruction. The prism or the cylinder can also be hollow.

The machine element is preferably formed by a shaft, by a hollow shaft,by a shifting fork, or by a flange. The shaft, the shifting fork, or theflange can be designed for loading by different forces and moments. Inprinciple, the machine element can also be formed by completelydifferent types of machine elements.

The at least two magnetic field sensors are preferably each formed by asemiconductor sensor. Such semiconductor sensors directly enable themeasurement of multiple directional components of the magnetic field.The at least two magnetic field sensors or the magnetic field sensorelements comprised by the magnetic field sensors are alternativelyformed preferably by Hall sensors, coils, saturable reactors, or fluxgate magnetometers. In principle, other types of sensors could also beused, if they are suitable for measuring an individual or multipleindividual directional components of the magnetic field caused by theinverse magnetostrictive effect.

The method according to the invention is used for measuring a forceand/or a moment. The force and/or the moment acts on a machine elementextending along an axis. The machine element has a magnetization areaextending about the axis for a magnetization extending about the axis.The force or the moment is measured in at least two differentcircumferential positions about the axis. In these two positions, atleast two differently oriented directional components of a magneticfield caused by the magnetization and by the force and/or by the momentare determined.

One particular advantage of the method according to the invention isprovided in that it enables the flexible measurement of differentdirectional components of the force and moment that occur.

The method according to the invention is preferably performed on thearrangement according to the invention and its preferred embodiments.Incidentally, the method according to the invention preferably also hasthose features that are specified in connection with the arrangementaccording to the invention and its preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional details, advantages, and refinements of the invention areproduced from the following description of preferred embodiments of theinvention with reference to the drawing. Shown are:

FIG. 1 a first preferred embodiment of the arrangement according to theinvention with four magnetic field sensors;

FIG. 2 a second preferred embodiment of the arrangement according to theinvention with four magnetic field sensors;

FIG. 3 a third preferred embodiment of the arrangement according to theinvention with four magnetic field sensors;

FIG. 4 a fourth preferred embodiment of the arrangement according to theinvention with three magnetic field sensors;

FIG. 5 a fifth preferred embodiment of the arrangement according to theinvention with three magnetic field sensors;

FIG. 6 a sixth preferred embodiment of the arrangement according to theinvention with three magnetic field sensors;

FIG. 7 a seventh preferred embodiment of the arrangement according tothe invention with two magnetic field sensors; and

FIG. 8 an eighth preferred embodiment of the arrangement according tothe invention with four magnetic field sensors;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 to FIG. 7 show the arrangements according to the invention eachin two views. The left part of each figure is a cross-sectional view,while the right part of each figure is a top view of the respectiveembodiment of the arrangement according to the invention.

FIG. 1 shows a first preferred embodiment of the arrangement accordingto the invention. The arrangement first comprises a machine element inthe form of a flange 01 that is mounted on a base body 02. The flange 01has the shape of a hollow circular cylinder. The flange 01 extends alongan axis 03 that also forms the center axis of the hollow cylindricalshape of the flange 01. The flange 01 is formed of a magnetoelasticmaterial that has the magnetostrictive effect.

In an axial section of the flange 01, a permanent magnetization area 04is formed that extends circumferentially about the axis 03.

Four magnetic field sensors 11, 12, 13, 14 that have an equal distanceto the axis 03 and are arranged distributed equally about this axis arearranged circumferentially about the flange 01. The four magnetic fieldsensors 11, 12, 13, 14 are opposite the permanent magnetization 04. Thefour magnetic field sensors 11, 12, 13, 14 are each formed by asemiconductor sensor. The four magnetic field sensors 11, 12, 13, 14 areformed to each individually measure three directional components of amagnetic field B. This suitability can alternatively be given such thatthe magnetic field sensors each comprise three magnetic field sensorelements (not shown) for measuring one of the directional components.

The three Cartesian directions x, y, and z are shown, wherein the axis03 is in the x direction. Furthermore, for each of the four magneticfield sensors 11, 12, 13, 14, the respective measurable directionalcomponents of the magnetic field B are indicated. The indicateddirectional components have a first suffix, wherein r stands for aradial direction, a for an axial direction, and t for a tangentialdirection with respect to the axis 03. The indicated directionalcomponents have a second suffix that indicates a rotational angle α indegrees. The rotational angle α is spanned between the position of eachof the magnetic field sensors 11, 12, 13, 14 and the z-axis. Because thefour magnetic field sensors 11, 12, 13, 14 are arranged distributedequally about the axis 03, the rotational angle α=0°, 90°, 180°, or270°.

With the illustrated embodiment of the arrangement according to theinvention, the three directional components Mx, My, and Mz of a momentacting on the flange 01 and the directional components Fy and Fz of aforce acting on the flange 01 can be measured. The followingrelationships apply:

$\begin{matrix}{{M_{x} = {{{k_{1} \cdot {()}}\mspace{14mu}{or}\mspace{20mu} M_{x}} = {{{k_{2} \cdot ( + )}\mspace{14mu}{or}\mspace{14mu} M_{x}} = {k_{3} \cdot \left( {+ {B_{a\; 270}}} \right)}}}}\mspace{79mu}{M_{y} = {{{k_{4} \cdot \left( {- {B_{t\; 108}}} \right)}\mspace{14mu}{or}\mspace{14mu} M_{y}} = {k_{5} \cdot \left( {- {B_{r\; 270}}} \right)}}}\mspace{79mu}{= {{{k_{6} \cdot \left( {- {B_{r\; 180}}} \right)}\mspace{14mu}{or}\mspace{14mu} M_{z}} = {k_{7} \cdot \left( {- {B_{t\; 270}}} \right)}}}\mspace{79mu}{F_{y} = {k_{8} \cdot \left( {{B_{a\; 0}} - {B_{a\; 180}}} \right)}}\mspace{79mu}{F_{z} = {k_{9} \cdot \left( {B_{a\; 90} - {B_{a\; 270}}} \right)}}\mspace{79mu}{k_{1},k_{2},k_{3},k_{4},k_{5},k_{6},k_{7},k_{8},{k_{9}:{constants}}}} & \;\end{matrix}$

FIG. 2 shows a second preferred embodiment of the arrangement accordingto the invention. This embodiment is initially equal to the embodimentshown in FIG. 1. Deviating from the embodiment shown in FIG. 1, the fourmagnetic field sensors 11, 12, 13, 14 are formed to individually measureonly two directional components of the magnetic field B, namely in theaxial direction and in the tangential direction. This suitability can bealternatively given such that the magnetic field sensors each have twomagnetic field sensor elements (not shown) for measuring one of the twodirectional components.

The following relationships apply:

$\begin{matrix}{{M_{x} = {{{k_{1} \cdot {()}}\mspace{14mu}{or}\mspace{20mu} M_{x}} = {{{k_{2} \cdot ( + )}\mspace{14mu}{or}\mspace{14mu} M_{x}} = {k_{3} \cdot \left( {+ {B_{a\; 270}}} \right)}}}}\mspace{79mu}{M_{y} = {k_{4} \cdot \left( {- {B_{t\; 108}}} \right)}}\mspace{14mu}\mspace{79mu}{M_{z} = {k_{7} \cdot \left( {- {B_{t\; 270}}} \right)}}\mspace{79mu}{F_{y} = {k_{8} \cdot \left( {{B_{a\; 0}} - {B_{a\; 180}}} \right)}}\mspace{79mu}{F_{z} = {k_{9} \cdot \left( {B_{a\; 90} - {B_{a\; 270}}} \right)}}\mspace{79mu}{k_{1},k_{2},k_{3},k_{4},k_{7},k_{8},{k_{9}:{constants}}}} & \;\end{matrix}$

FIG. 3 shows a third preferred embodiment of the arrangement accordingto the invention. This embodiment is initially equal to the embodimentshown in FIG. 1. Deviating from the embodiment shown in FIG. 1, the fourmagnetic field sensors 11, 12, 13, 14 are formed to individually measureonly two directional components of the magnetic field B, namely in theaxial direction and in the radial direction. This suitability canalternatively be given such that the magnetic field sensors eachcomprise two magnetic field sensor elements (not shown) for measuringone of the two directional components.

The following relationships apply:

$\begin{matrix}{{M_{x} = {{{k_{1} \cdot {()}}\mspace{14mu}{or}\mspace{20mu} M_{x}} = {{{k_{2} \cdot ( + )}\mspace{14mu}{or}\mspace{14mu} M_{x}} = {k_{3} \cdot \left( {+ {B_{a\; 270}}} \right)}}}}\mspace{79mu}{M_{y} = {k_{5} \cdot \left( {- {B_{r\; 270}}} \right)}}\mspace{79mu}{= {k_{6} \cdot \left( {- {B_{r\; 180}}} \right)}}\mspace{14mu}\mspace{79mu}{F_{y} = {k_{8} \cdot \left( {{B_{a\; 0}} - {B_{a\; 180}}} \right)}}\mspace{79mu}{F_{z} = {k_{9} \cdot \left( {B_{a\; 90} - {B_{a\; 270}}} \right)}}\mspace{79mu}{k_{1},k_{2},k_{3},k_{5},k_{6},k_{8},{k_{9}:{constants}}}} & \;\end{matrix}$

FIG. 4 shows a fourth preferred embodiment of the arrangement accordingto the invention. This embodiment is initially equal to the embodimentshown in FIG. 1. Deviating from the embodiment shown in FIG. 1, onlythree of the magnetic field sensors 11, 12, 13 are present. The threemagnetic field sensors 11, 12, 13 are distributed equally about the axis03, so that the rotational angle α=0°, 120°, or 240°.

The following relationships apply:

M_(x) = k₁ ⋅ (B_(a 0) + B_(a 120) + B_(a 2 40))M_(y) = k₄ ⋅ ()  or  M_(y) = k₅ ⋅ (−1/2 ⋅ ()) = k₆ ⋅ (−)  or  M_(z) = k₇ ⋅ (−1/2 ⋅ (B_(r 120) + B_(r 240)))F_(y) = k₈ ⋅ (−1/2 ⋅ (+)) F_(z) = k₉ ⋅ (−B_(a 240))k₁, k₄, k₅, k₆, k₇, k₈, k₉ : constants

FIG. 5 shows a fifth preferred embodiment of the arrangement accordingto the invention. This embodiment is initially equal to the embodimentshown in FIG. 4. Deviating from the embodiment shown in FIG. 4, thethree magnetic field sensors 11, 12, 13 are formed to individuallymeasure only two directional components of the magnetic field B, namelyin the axial direction and in the tangential direction. This suitabilitycan alternatively be given such that the magnetic field sensors eachcomprise two magnetic field sensor elements (not shown) for measuringone of the two directional components.

The following relationships apply:

M_(x) = k₁ ⋅ () M_(y) = k₅ ⋅ (−1/2 ⋅ ())M_(z) = k₆ ⋅ (B_(t 120) − B_(t 240)) F_(y) = k₈ ⋅ (−1/2 ⋅ (+))F_(z) = k₉ ⋅ () k₁, k₅, k₆, k₈, k₉ : constants

FIG. 6 shows a sixth preferred embodiment of the arrangement accordingto the invention. This embodiment is initially equal to the embodimentshown in FIG. 4. Deviating from the embodiment shown in FIG. 4, thethree magnetic field sensors 11, 12, 13 are formed to individuallymeasure only two directional components of the magnetic field B, namelyin the axial direction and in the radial direction. This suitability canalternatively be given such that the magnetic field sensors eachcomprise two magnetic field sensor elements (not shown) for measuringone of the two directional components.

The following relationships apply:

M_(x) = k₁ ⋅ () M_(y) = k₄ ⋅ (B_(r 120) − B_(r 240))M_(z) = k₇ ⋅ (−1/2 ⋅ (+)) F_(y) = k₈ ⋅ (−1/2 ⋅ (+)) F_(z) = k₉ ⋅ ()k₁, k₄, k₇, k₈, k₉ : constants

FIG. 7 shows a seventh preferred embodiment of the arrangement accordingto the invention. This embodiment is initially equal to the embodimentshown in FIG. 1. Deviating from the embodiment shown in FIG. 1, only twoof the magnetic field sensors 12, 14 are present. The two magnetic fieldsensors 12, 14 are distributed equally about the axis 03, so that therotational angle α=90° or 270°.

The following relationships apply:

 M_(x) = k₃ ⋅ () M_(y) = k₅ ⋅ (B_(r 90) − B_(r 270)) M_(z) = k₇ ⋅ (−)F_(z) = k₉ ⋅ () k₃, k₅, k₇, k₉ : constants

FIG. 8 shows an eighth preferred embodiment of the arrangement accordingto the invention. This embodiment is initially equal to the embodimentshown in FIG. 1. Deviating from the embodiment shown in FIG. 1, theflange extends only in a first section 16 along the axis 03, so that theaxis 03 forms a first axis 03. In a second section 17, the flange 01extends along a second axis 18 that is perpendicular to the first axis03.

The flange 01 has, in its second section 17, a second permanentmagnetization area 19, so that the permanent magnetization area 04 inthe first section 16 forms a first permanent magnetization area. The twomagnetic field sensors 12, 14 are allocated to the first permanentmagnetization area 04. In the same way, a first magnetic field sensor 21and a second magnetic field sensor 22 are allocated to the secondpermanent magnetization area 19.

With the four magnetic field sensors 12, 14, 21, 22, all threedirectional components Mx, My, and Mz of the moment acting on the flange01 and all three directional components Fx, Fy, and Fz of the forceacting on the flange 01 can be measured. Here, alternatively another ofthe magnetic field sensor arrangements shown in FIG. 1 to FIG. 7 canalso be selected for the two sections 16, 17 of the flange 01. Aprerequisite for this is that the force causing the load or the momentcausing the load is applied in the second section 17 of the flange 01.

LIST OF REFERENCE NUMBERS

-   01 Flange-   02 Base body-   03 Axis-   04 Permanent magnetization area-   05 --   06 --   07 --   08 --   09 --   10 --   11 First magnetic field sensor-   12 Second magnetic field sensor-   13 Third magnetic field sensor-   14 Fourth magnetic field sensor-   15 --   16 First section-   17 Second section-   18 Second axis-   19 Second permanent magnetization area-   20 --   21 First magnetic field sensor allocated to the second section-   22 Second magnetic field sensor allocated to the second section

The invention claimed is:
 1. An arrangement for measuring at least oneof a force or a moment on a machine element, the machine elementincluding a first section extending along a first axis, in which themachine element includes a first magnetization area for a firstmagnetization extending circumferentially around the first axis, thearrangement further comprises at least one first magnetic field sensorand one second magnetic field sensor each of which are formed forindividually measuring a first and a second directional component of amagnetic field caused by the first magnetization and by the at least oneof the force or the moment, wherein the first directional component ofthe magnetic field measurable with the first magnetic field sensor andthe second directional component of the magnetic field measurable withthe first magnetic field sensor have different orientations, wherein thefirst directional component of the magnetic field measurable with thesecond magnetic field sensor and the second directional component of themagnetic field measurable with the second magnetic field sensor havedifferent orientations, and the first magnetic field sensor and thesecond magnetic field sensor are arranged at different circumferentialpositions about the first axis, wherein the machine element furthercomprises a second section in which the machine element extends along asecond axis arranged perpendicular to the first axis, the second sectionhas a second magnetization area for a second magnetization extendingcircumferentially about the second axis.
 2. The arrangement according toclaim 1, wherein the first magnetization area is permanently magnetized,so that the first magnetization is formed by a permanent magnetization.3. The arrangement according to claim 1, wherein the first magnetizationarea has a ring-shaped construction around the first axis.
 4. Thearrangement according to claim 1, wherein the at least two magneticfield sensors each comprise two or three magnetic field sensor elementsthat are each formed for measuring one of the directional components ofthe magnetic field caused by the first magnetization and by the at leastone of the force or the moment.
 5. The arrangement according to claim 1,wherein the directional components measurable with the at least twomagnetic field sensors are selected from the group: a direction parallelto the first axis, a direction radial to the first axis, or a directiontangential to the first axis.
 6. The arrangement according to claim 1,wherein the at least two magnetic field sensors are each further formedfor measuring a third directional component of the magnetic field causedby the first magnetization and by the at least one of the force or themoment.
 7. The arrangement according to claim 1, wherein the at leasttwo magnetic field sensors have an identical distance to the first axis.8. The arrangement according to claim 1, wherein the at least twomagnetic field sensors are arranged distributed equally about the firstaxis.
 9. The arrangement according to claim 1, wherein the arrangementfurther comprises at least one additional first magnetic field sensorallocated to the second section and an additional second magnetic fieldsensor allocated to the second section each of which are constructed forindividually measuring at least a first and a second directionalcomponent of a magnetic field caused by the second magnetization and bythe at least one of the force or the moment, the first directionalcomponent measurable with the additional first magnetic field sensorallocated to the second section and the second directional componentmeasurable with the additional first magnetic field sensor allocated tothe second section have different orientations, the first directionalcomponent measurable with the additional second magnetic field sensorallocated to the second section and the second directional componentmeasurable with the additional second magnetic field sensor allocated tothe second section have different orientations, and the additional firstmagnetic field sensor allocated to the second section and the additionalsecond magnetic field sensor allocated to the second section arearranged at different circumferential positions about the second axis.10. A method for measuring at least one of a force or a moment, whereinthe force or the moment acts on (1) a first section of a machine elementthat extends along a first axis and has a first magnetization areaextending about the first axis for a first magnetization extending aboutthe first axis, and (2) a second section of the machine element thatextends along a second axis arranged perpendicular to the first axis,and the second section has a second magnetization area for a secondmagnetization extend about the second axis, the method comprising:measuring the at least one of the force or the moment in at least twodifferential circumferential positions about the first axis and thesecond axis at each of which at least two directional components withdifferent orientations of a magnetic field caused by the firstmagnetization and the second magnetization and by the at least one ofthe force or the moment are determined.